Usually, an exhaust gas treatment device such as for example a particle filter or a catalytic converter comprises a housing, the jacket of which encloses an accommodation space in circumferential direction, wherein in the accommodation space at least one exhaust gas treatment element is arranged, which can be for example a particle filter element or a catalyst element. Such exhaust gas treatment elements can for example have a ceramic basic body, which in particular can have a monolithic structure. Such ceramic exhaust gas treatment elements are comparatively sensitive to shock loads and must therefore be mounted in the housing or in the jacket in a shock-absorbing manner. Accordingly, a usual exhaust gas treatment device additionally comprises a bearing layer of an elastic bearing material, which encloses the respective exhaust gas treatment element in the circumferential direction.
Since such a bearing layer in conventional design additionally serves to fix the respective exhaust gas element in position in the housing, the respective exhaust gas treatment element and the housing jacket are crimped together with the bearing layer arranged between. The bearing materials used in this case are selected so that a desired holding force and the absorbing effect for the respective exhaust gas treatment element can be ensured throughout the usual temperature range of the exhaust gas treatment device. In this case, the bearing layer has to balance temperature expansion coefficients on the one hand of the metallic jacket and on the other hand of the ceramic exhaust gas treatment element.
In modern exhaust gas treatment devices, a thermal insulation can be additionally provided, which encloses the housing or the jacket on an outside in order to reduce the thermal load of the surroundings. Such a design however is disadvantageous in multiple respects. On the one hand, the insulation arranged on the outside of the jacket has to be fixed, which can for example be realized with a further metallic sleeve, which encloses the jacket. This design is comparatively involved and expensive. On the other hand, higher temperatures result for the jacket arranged radially between the insulation and the bearing layer, since the insulation located on the outside prevents cooling of the jacket. These higher temperatures in the jacket result in greater thermally-induced relative movements between the jacket and the respective exhaust gas treatment element, as a result of which the mounting of the respective exhaust gas treatment element is weakened. At the same time, a higher corrosion load results for the jacket. In order to remedy this, a more expensive material can be utilized for the jacket which has a higher corrosion resistance and/or a lower temperature expansion coefficient.
From DE 10 2008 048 314 A1 an exhaust gas treatment device for an exhaust system of an internal combustion engine is known, the housing of which comprises a jacket located inside, which encloses an accommodation space in the circumferential direction, and a jacket located outside, which encloses the jacket located inside and thus likewise which encloses an accommodation space in the circumferential direction. Furthermore, the exhaust gas treatment device comprises an exhaust gas treatment element, which is arranged in the accommodation space, as well as a bearing layer of an elastic bearing material, which encloses the exhaust gas treatment element in the circumferential direction, radially lies against said exhaust gas treatment element with a pressure force, transmitting this pressure force onto the jacket force located inside. Because of this, the exhaust gas treatment element is fixed in position relative to the jacket located inside. Furthermore, the known exhaust gas treatment device comprises an insulating layer of a thermally insulating insulating material, which encloses the jacket located inside and thus also the bearing layer and the exhaust gas treatment element in the circumferential direction within the jacket located outside. In this case, the insulating layer lies against the jacket located outside and is braced against the jacket located inside via webs so as to position it in the jacket located outside. In addition to this, the known exhaust gas treatment device is equipped with a metal foil, which is radially arranged between the bearing layer and the jacket located inside.